1. Field of the Invention
The present invention relates generally to input units for data processors, and more particularly to a manual input unit to enter information into a computer or the like by a hand operation. The present invention may be particularly suitable for use in an amusement computer, e.g., a game machine.
2. Description of the Related Art
Recently, various operation systems or applications, in which a pointing device with an excellent manual operability is used in addition to a keyboard as an information entering means for a computer or the like, for processing data through an interactive operation by freely shifting a character or a cursor on a display screen, have been developed. Also, in an amusement computer, e.g., a game machine, various manual input units such as a joystick have been used. The manual input unit used for such an amusement application generally requires some properties different from those of conventional manual input units for ordinary computers.
For example, in a known manual input unit for an amusement computer, which is operated by an operator holding the body of the unit with one or both hands, a weight reduction in the unit and an improvement in operability are required. Also, since various ages of operators, ranging from infants to adults, tend to operate the input unit in various ways, it is preferred that the unit includes a stably operative movable part which is hardly affected by variations in operating parameters such as an inclination of the unit body, vibration applied to the unit body or external forces applied to an actuating section of the unit.
In addition, since this type of manual input unit may be used indoors and outdoors, it is required that an output data signal of the unit is immune to an environmental temperature change. Also, it is desired that the input unit has a relatively simple structure which can reduce the manufacturing cost thereof, considering the maintenance or the parts replacement of the input unit when a defect occurs therein. Thus, there are demands for a manual input unit, particularly in the field of amusement computers, which can reduce the manufacturing cost thereof, can be easily handled and can decrease the possibility of a malfunction due to vibration or a temperature change.
FIG. 9 schematically shows a widely used amusement computer system with a manual input unit. FIG. 10 illustrates an example of the structure of a conventional manual input unit. FIGS. 11A and 11B show the relationship between an output signal and a displacement of actuator in the conventional manual input unit.
The amusement computer system shown in FIG. 9 includes a computer 1 as a game machine, a display 2 for displaying an image, and an manual input unit 3 for entering information, both the display 2 and the input unit 3 being connected to the computer 1. By operating the manual input unit 3, it is possible to freely set a one-dimensional parameter in a game, such as a beam magnitude of a laser gun or a speed of a car, or freely shift a character or a cursor displayed on the display 2 in a two-dimensional manner.
As shown in FIG. 10, the manual input unit 3, which is one example of the input units used in the above amusement computer system, includes a frame 32 having a grip 31 to be grasped by the operator with one or both hands, a generator section 35 and a signal transmission section 36 both fixedly arranged in the frame 32, and a movable actuator section 45 pivotably supported on the frame 32. The frame 32 is generally molded with a resinous material excellent in mechanical strength and capable of easily reducing a weight of the frame.
The generator section 35 includes a printed circuit board 33 fixed to a predetermined position in frame 32, and two magnetoelectric elements 37, such as Hall elements, spaced from each other and mounted on the printed circuit board 33. The signal transmission section 36 is provided with a printed circuit board 34 fixed at a predetermined position in the frame 32 away from the printed circuit board 33, and a CPU 38 mounted on the printed circuit board 34.
The movable actuator section 45 includes a trigger 41 pivoted to the frame 32 by a pin 42 disposed near the grip 31, and a compression coil spring 43 interposed between the frame 32 and the trigger 41 to bias the trigger 41 toward a start position as illustrated. A permanent magnet 44 is fixed on a side surface of a distal end of the trigger 41 away from the pin 42. The magnet 44 acts as a counterpart element for the magnetoelectric elements 37 of the generator section 35 to make the magnetoelectric elements 37 generate a voltage. When the trigger 41 is at the start position, a stopper 46 formed along the lower edge of the trigger is abutted to the inner wall of the frame 32 to inhibit the further rotation of the trigger. In this state, the trigger partially projects forward through an opening 40 formed near the grip 31.
The operator grasps the grip 31 with one hand in a similar manner to the hand operation for a pistol, and squeezes the trigger 41 by finger pressure on the part of the trigger 41 projecting from the opening 40. Thereby, the trigger 41 rotates about the pin 42 in a clockwise direction as seen in the drawing from the start position. Simultaneously, the permanent magnet 44 fixed to the end of the trigger moves upward along an arcuate path about the pin 42 from a lowermost position as illustrated to an uppermost position (not shown).
The two magnetoelectric elements 37 of the generator section 35 are fixed on the printed circuit board 33, so as to be respectively located near the lowermost and uppermost positions of the permanent magnet 44, and do not come into contact with the permanent magnet 44 irrespective of the position of the magnet 44. When the permanent magnet 44 moves along the arcuate path, an output voltage generated from each magnetoelectric element 37 varies in linear correspondence to a variation of the distance between each magnetoelectric element and the permanent magnet 44. The output voltage from each magnetoelectric element 37 is converted to a digital signal and then is passed to the signal transmission section 36.
In the signal transmission section 36 fixed to the upper portion of the frame 32, when the output-voltage value is entered from the generator section 35 to the CPU 38, the CPU 38 selects or retrieves data corresponding to the voltage value from a number of stored data (e.g., data for beam magnitudes of a laser beam gun), and transmits a data signal to the external computer 1 via a coupling cable 39.
For example, the output voltage from the magnetoelectric element 37 located near the uppermost position of the permanent magnet 44 increases in a generally linear manner in proportion to the increase of a displacement of the trigger 41 from the start position, as shown in a solid line in FIG. 11A (the displacement being shown as a linear stroke converted from an angular distance). In this regard, since the magnetoelectric element 37 such as a Hall element is generally susceptible to an environmental temperature change, the characteristic curve shown by the solid line may be shifted or translated to, e.g., another characteristic curve shown by a dotted line, as an environmental temperature varies. As a result, the voltage generated by the magnetoelectric element 37 when the trigger 41 is e.g., at the start position (i.e., displacement=0), may be shifted to a voltage "b" from an intrinsic voltage "a", due to the environmental temperature change.
In the case that the CPU 38 is programmed so as to transmit data "0" in response to the input voltage "a" and data 256 in response to the input voltage "c", as shown in FIG. 11B, if a voltage "b" is erroneously entered due to the temperature change when the trigger 41 is in the start position, data "d" might be transmitted, which is different from the intrinsic data "0". As a result, the computer 1 may operate in such a manner as to not conform to a command from the manual input unit 3.
To solve such problems, in the manual input unit 3 described above, two magnetoelectric elements 37 are respectively arranged near the lowermost and uppermost positions of the arcuate path of the permanent magnet 44, and connected to each other to output a voltage, in a differential manner, from both elements 37, so that the data can be selected in response to the differential voltage value of two output voltages of both elements 37, while maintaining the relationship shown in FIG. 11B. According to this arrangement, since output voltages of both magnetoelectric elements 37 vary in the same manner as the environmental temperature varies, the variations in the output voltages of both elements are cancelled by adopting the differential value of those output voltages. Thus, it is possible to transmit data which accurately corresponds to the displacement of the trigger 41, without affecting the data selection.
The manual input unit for the amusement computer described above is adapted to transmit data corresponding to the displacement of the movable actuator section by using the magnetoelectric elements and the permanent magnet which cannot come into contact with each other, so that certain advantages are obtained, i.e., a weight reduction of the unit and an improvement in operability can be accomplished, and also the generator section and the signal transmission section are hardly susceptible to vibration and external forces during the operation and thus can be stably operated. In addition, since two magnetoelectric elements are used, it is possible to eliminate the effect of the environment temperature change, and thus to translate a data signal correctly corresponding to the displacement of the movable actuator section so that the external processing unit operates in conformation to a command.
However, this manual input unit still has problems in that, since it is necessary to use two relatively expensive magnetoelectric elements for eliminating the effect of the environmental temperature change, which in turn requires an additional printed circuit board separate from the signal transmission section for mounting the magnetoelectric elements near the lowermost and uppermost positions of the arcuate path of the permanent magnet, the structure of the unit becomes more complicated to increase the production cost thereof.